The present invention concerns a tactile stimulation device capable of transforming an audio signal into vibrations which can be sensed by the skin of a person.
The field of the invention is of special interest to deaf persons or to persons with a hearing deficiency whose auditory apparatus is deficient or nonfunctional.
In order for a deaf person to be able to understand a speaker, the most commonly known method consists in that this person learns to read lips.
There are, however, situations in which this person cannot see the speaker, for example, during operation of an intercom or when the person is attempting to respond at the end of a message from the speaker transmitted by an intercom.
There is also a real need to reinforce the capability of communication between a deaf person and a speaker during lip reading by helping the person perceive the vibrational differentiation of the various phonemes and also by enabling him to adjust his voice as a function of the ambient sound.
Attempts have been made to resolve this problem by proposing tactile stimulation devices including, generally, a microphone connected to a case including an electric current source as well as an electronic circuit board designed to convert the electrical signal provided by the microphone into an electrical signal designed to actuate an electroacoustic transducer.
An electroacoustic transducer is connected to the case and is held against the skin of the person, for example, by a bracelet putting the transducer into contact with the wrist of the person wishing to use it.
After learning a technique for recognition of the vibrations transmitted by the electroacoustic transducer to the skin of the person, the person is capable of interpreting the vibrations received by the skin and transmitted to the brain by the nerve endings of the skin, so as to understand the speech of the speaker.
However, this type of device does not give complete satisfaction because it is cumbersome, necessitates electrical links between its various components, and imposes the permanent wearing of a bracelet or of a device to affix the transducer on the skin.
Moreover, the human skin cannot sense vibrations whose frequency is greater than 1000 Hz.
Whereas the human voice produces sounds whose highest frequencies for intelligibility are in the frequency band from 1000 to 3000 Hz, the same is true for the passband of intercoms and telephones which extends up to 3000 Hz.
Thus, it seemed interesting to be able to take advantage of the data of the human voice in the frequency band from 1000 to 3000 Hz to use them in the device of the invention.
The first object of the invention is thus to propose a tactile stimulation device of compact construction and extremely simple to implement.
Another object of the invention is to propose a tactile stimulation device which makes use of the data transmitted in the human voice, of which the frequency is between 1000 and 3000 Hz.
To that end, the device of the invention includes, in particular, an electroacoustic transducer and is characterized in that it is made up of a case which can be held in one hand and which has a sensor associated with the electroacoustic transducer, which sensor is designed to permit turning on the device by touching said sensor.
Thus, the device of the invention is compact and easy to actuate.
According to another characteristic of the invention, the sensor consists of an insulating support provided with conductive strips electrically isolated from each other and connected to the input of a contact detector.
According to another characteristic of the invention, each conductive strip is spiral-shaped and they are interlaced.
According to another characteristic of the invention, the sensor is pressed against the diaphragm of the electroacoustic transducer.
According to another characteristic of the invention, the device has a lowpass frequency filter which selects the frequencies below 800 Hz.
According to another characteristic of the invention, the device has a passband frequency filter connected to a frequency generator capable of modulating the signal received from said frequency filter in amplitude on a specified frequency.
According to another characteristic of the invention, the passband frequency filter selects the range of frequencies between 1000 Hz and 4000 Hz.
According to another characteristic of the invention, the operating frequency of the frequency generator is 900 Hz.
Thus, the high-pitched frequencies of the voice are transcribed by the device of the invention.
According to another characteristic of the invention, the power button of the device can assume a STOP position designed to cut the electric power to the device, an ON position, and a STANDBY position capable of turning on the device by means of the contact detector.
According to another characteristic of the invention, the device has an input connector provided to accommodate a removable microphone or a reception accessory T such as a magnetic loop receiver.
According to another characteristic of the invention, the device has an output connector provided to accommodate an external electroacoustic transducer.
According to another characteristic of the invention, the device has a control knob making it possible to use a potentiometer in order to modulate the intensity of the electric current supplying the electroacoustic transducer.